In recent days, communication traffic relayed by a relay device like a repeater increases with significant increase of the number of wireless terminal devices. Accordingly, there is proposed a distributed trunking wireless communication system which causes a wireless terminal device to select at least one relay device among plural relay devices which are connected together via predetermined communication lines when the wireless terminal device communicates with another wireless terminal device. In such trunking wireless communication system, each wireless terminal device calls through a channel of a repeater to establish a communication path with a communication-counterparty wireless terminal device. The repeater notifies information indicating whether a current channel is busy or idle through a frame which is a unit of wireless signal to wireless terminal devices in an area. Conventionally, several trunking wireless communication systems have been proposed.
For example, in Patent Literature 1, a dispatcher of a trunking wireless communication system (a trunk wireless system) functions as a management center for plural wireless terminal devices. According to Patent Literature 1, when the dispatcher is registered in a base station, the base station relays a communication between wireless terminal devices via the dispatcher, so that the dispatcher enables a simultaneous multicasting communication to each wireless terminal device, and enables an allocation of another wireless terminal device instead of a faulty wireless terminal device.
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2007-36488